There seems to be a competition among YouTube reviewers on who can review new toys first. As a result they don't take enough time to properly explore and assess the toys' quality. One thing that is good though is that we get to see how they transform.
I think a healthy way to respond to the inverted FOMO would be to do what you described where you'd buy the figure, and if you don't end up liking it (or if something better comes along); sell it. Problem with me is that I don't like selling toys. Mainly because when I sell them, I usually sell at a loss, and I find the activity of packing them away and looking for buyers to be a chore. I'm basically a lazy bean counter. My remedy against this has been to tell myself "Only buy the toy IF you like it 100%". This leads me to search for faults and heavily criticize figures I like before deciding whether to buy. I often end up skipping them for very superficial reasons only to regret it later, which isn't good.
I also usually assume that newer toys will be better than older ones, and I tell myself things like "This Hot Rod is good, but I'll wait for a better version". As you mentioned, the newer toys aren't always better (or more appropriate) than previous versions. My example earlier with the CW Starscream actually happened with me, where I saw it IRL and thought "It's good, but I'll wait the next G1 Starscream. Starscream's popular, so it shouldn't be long til the next one". Then surprise, the PotP Starscream released 2-3 years later turns out to be less appealing than the CW version
I think if you like Dai Altas and lesser known characters like that, it's good to get them now.
The nice thing about popular characters like G1 Optimus Prime, Megatron, and Bumblebee is that you can almost count on HasTak to release new toys of those characters every 1 or 2 years. If you want a Neo-G1 Megatron but don't like the current one, you can maybe wait a year or two (if you're willing to play the long game) for the next one. The $30~$90 question is; "will the next one be better than the current one?" These things are hard to predict.
However, with lesser known characters like Dai Atlas, Flywheels and Triggerhappy, it's much harder to predict when we'll see these characters in toy form again. The previous toy released of Triggerhappy prior to Titans Return was the first release in 1987. That's a 30 year interval! Since G1 has gotten more popular in recent years, I don't think the intervals will be as wide, but it could still be many years until we see another Triggerhappy toy again, especially since there are still other G1 characters who still haven't gotten Neo-G1 (or CHUG) figures yet - like Piranacon, the Autobot Target Masters, Thunderclash, etc.
I think this is why there was so much FOMO in the air during the Titans Return days. Many people dislike the headmaster gimmick, and it's understandable - it sucks when you lose the head, and doesn't feel good to have to pull the head off during transformation. However at the same time, people who disliked headmasters still went bananas over the likes of TR Topspin, Twintwist, Quake, Repugnus, Misfire, etc. It's because they felt this could be the only opportunity they'll get in a long time to buy these characters at RRP. If they skip them now, they might have to wait like 9 years for newer versions of those characters (or pay secondary market prices for the toys they skipped or missed out on). It's very hard to predict when you'll be able to get a character like Dai Atlas again, so it's good to lock it in now.