Each to his own.
Buying online and using return policies and distance selling regulations sounds great on the surface, but unless it works out, it's a PITA for everyone. As a buyer you have the hassle of beginning the returns process, passing the item(s) to the courier and waiting what is sometimes several days for the refund (up to 10 working days in some cases, to give the retailer/warehouse time to check the condition of the returned items. Sometimes, you also incur the courier costs.
For the retailer, it means additional logistics, processing time (including the condition checks and refund), and stock they then have to sell at a discount. Their margin is squeezed by both the cost of the time, and the reduced selling price. Margins on a lot of electronics and speakers aren't that great in the first place, and these are businesses, not altruistic organisations. It isn't a great experience for either side.
Research is a very good thing to do, I agree, but looking at a spec sheet (which can be more or less accurate depending on the manufacturer) only goes so far, and the rest is down to the personal opinions of others. Most of the YouTube reviewers are a bit crackers TBH, and there are only a couple I would hold much confidence in. There's a bit more chance of getting it right if you know the general signature sound of the brands, but that can be quite variable too, for example the Radia A5 is quite a different sounding amplifier to the SA10. Those who didn't get on with the latter because it was slow and dirge-like sounding (including me) might discount the newer model without hearing how much more drive and rhythmic prowess it has.
If you're re-purchasing things you had in the past, this can be done a little more confidently, but aural memory can be deceptive, and if buying secondhand, different examples of the same make and model may have aged differently due to amount of use, operating conditions, the quality of any repairs, differences in replaced capacitors etc.
Buying online is no more or less a PITA for anyone than it is buying gear in a store and then you need to return it because there's a problem with the gear.
But let's say you do need to return something you bought online - you mention all the steps Matt, but the "hassle" is notifying the seller / dealer that the item's not for you or it's faulty and you return it. You might get a prepaid return, esp if faulty, after that, you just book the courier and they pick the item up. Return within 48 hours, tracked, job done. Refund issued within a week usually.
Why are we considering the retailer here? I'm purchasing in good faith with my hard earned tax dollars. The retailer is selling in good faith. They choose to sell online as well as maybe instore too, so they know what they sign up to when they opt to sell online. I've zero issues with a minor inconvenience for the retailer, but let's call this what it is - it's business.
And it's "not a great experience"? It's no worse than going into a dealer and asking if you can swap an item if you get it home and don't like it with your own setup and they tell you "well, we ... might ... be able to do something" (but mega non-committal) which is a massive red flag before the ultra-sucks experience that that would be.
Remember those days before buying online was an option? Sometimes, if you knew a dealer well, they'd let you take a bit of gear home and try it out for a weekend, or a day or two midweek. I'm not sure there's a whole lot of difference there than buying/trying via online really. Less if you consider you don't need to traipse into town (I'm 35 miles from the nearest dealer these days) with the kit you've borrowed, parked up somewhere, then lugged the thing back into the shop. So phoning a courier to do the lugwork sounds like a godsend to me.
I couldn't tell you one YouTuber that does reviews. I do occasionally catch John Darko's stuff, but he's been in the game for years at 6 Moons and a bunch of other titles long before he went into the online media sphere. See also Paul Rigby (The Audiophileman) formerly of the Hi Fi World parish. When I bought the Alva ST turntable from Cambridge, I picked up the What Hi Fi review - a 3 star one - and bought the deck. The review was a poor affair and other reviews elsewhere were more illuminating with more insight so it was easy to disregard the WHF one. The Cambridge 200M DAC was an easy pick, great sounding, fantastic connectivity and a winner, I use it mainly with the Wiim Pro Plus streamer, but occasionally with one of the spare CD players I have. The review sources include Stereophile, 6 Moons, Darko and Rigby, Hifi+, and a few other titles. These days, you can get accurate information on the product without relying on a half-page review that's barely worth the paper it's printed on.
Buying secondhand always comes with a caveat, but I've been pretty fortunate with my purchases there and kind of know what I'm looking for. The system is mostly set, the AVI actives aren't going anywhere soon, so I don't need to worry about amps or preamps, the hobby for me these days is mainly centred around older / vintage CD players from the likes of Kenwood, Pioneer and Sony. The box-swapping stopped years ago, the path to madness I found!
The main retailers I go with these days would be Tyson's who had a great sale a year or so back with Chord cables - the prices on my preferred Fisual Havana XLs went up and the Chord Shawlines were a very good price for a while, so I stocked up on several of those and a couple of pairs of the Clearways. Tyson's have been very good otherwise, much in the mould of Richer Sounds, although to be fair, I think the last thing I bought from RS was the Cambridge 752BD back in 2014 (and which is still in fine working order)!