Backing rpg kickstarters was my lockdown hobby, and they're just starting to come through now.
(Re the NFT thing - if kickstarter ever actually go live on blockchain/nft stuff, then I'm out, but if they're only choosing to frittering their money away on r&d in the area at this point, then I'll wait and see. I can't really hold them to a higher standard than my bank, for instance)
I expect significant time overruns all the time, and the smaller and newer a publisher, the bigger the overrun. Privateer Press and Kobold Press both delivered pretty close to on time (shipping was a different matter, but that's out of their hands), but I'm well over a year overdue for Age of Antiquity for instance (though i just got an email today that this one was printed and heading to distributors, finally!)
I used to have a more ruthless 'never back first timers' policy, but that's faded with time. First time publishers are doing some of the more interesting material out there (especially in the own-voices space, or novel/unusual settings or time periods) and I'm in a financial position where if a couple of $60 kickstarters turn out to be fly by night, it's annoying rather than a big deal. And I'm a bit more tolerant of overruns for first-time publishers too - they're learning lessons as they go, I always mentally budget in a couple of months of first-time-goof-up allowance.
Ironically, the campaign I backed that most annoyed me was the most successful and involved the biggest names. Tanares, which raised well over a million and should be rolling in resources, casually announced a month or two after funding that they'd arbitrarily decided to just ignore the rpg component of their campaign while they got the board game, miniatures etc done, and that they wouldn't even be touching the RPG for another 6 months. Given I only backed the RPG component, this was pretty frustrating and not an entirely ethical decision imho. Well, there was another guy who was running a kickstarter to produce the same campaign setting that he'd run a successful kickstarter to produce a few years earlier, and then largely failed to deliver on. But I unbacked him as soon as i realised what had happened.
Anything including miniatures or wallets or badges or other miscellanea, I avoid because they add little value to me but do add an extra production stream in which things can go wrong (I sometimes back campaigns that include miniatures, but i don't back at levels that includes the minis themselves). I prefer stretch goals that are actual extra content in the book, but I know that this sort of thing involves extra time in layout and stuff so i expect delays to be longer.
I do respect those publishers who are transparent and have strict update schedules - not necessarily monthly or anything so rigid, but they could just in each update, tell you when the next update will be and what progress they expect to have made by then. And then stick to it. I know they got a bit of flak on here for their subject matter, but credit where it's due, the people behind the Adventurer's Guide to the Bible have been absolutely exemplary on this front. Time and completion estimate breakdowns for the different stages of development, clear explanations of where the money is going, the causes of delays, the amount of time buffer they budgeted for delays, the lot. And it's helped that so far they're running bang on time or even a bit ahead of schedule. Anyone running a first-time kickstarter could be well advised to have a look how they've done it. Conversely, I've backed other campaigns where the target date is two months away and the publishers are still sourcing art and there's not a chance in hell the thing will be delivered on time, but they're refusing to actually say so. Be HONEST, ffs.