Yeah the cheapest time to buy old tech is always just when the new stuff has come out. That's when suppliers are trying to shift old stock at cheaper margins.
You can take a look at the 5800X3D and how it was at its cheapest about 2 years ago when AMD was winding down production and Zen 4 had been launched.
The main issue there is you need someway to pay the engineers in that transitional period the moment Mozilla collapses. Otherwise they leave, find new jobs, and you lose all the expertise and knowledge of the codebase.
That assumes you can add compute in a vacuum. If your altcoin receives 10x compute then it becomes 10x more expensive to mine.
That only scales if the coin goes up in value due to the extra "interest". Which isn't impossible but there's a limit, and it's more often to happen to smaller coins.
The one thing to be careful with Zen 2 onwards is that if your server is going to be idling most of the time then the majority of your power usage comes from the IO die. Quite a few times you'd be better off with the "less efficient" Intel chips because they save 10-20 Watts when doing nothing.
UUIDv7s are much worse for creation time though imo. For sequential IDs an attacker needs to be have a lot of data to narrow the creation time. That raises the barrier of entry considerably to the point that only a committed attacker could infer the time.
With UUIDv7 the creation time is always leaked without any sampling. A casual attacker could quite easily lookup the time and become motivated in probing and linking the account further
Then that's just worse and more complicated than storing a 64 bit bigint + 128 UUIDv4. Your salt (AES block) is larger than a bigint. Unless you're talking about a fixed value for the AES (is that a thing) but then that's peppering which is security through obfuscation.
There's been community forks of it since then that I switched to and will continue to use instead. Grouping tabs at the top is much worse UX than an entire page you can drag and drop around, and blatantly copying Chrome.
You can take a look at the 5800X3D and how it was at its cheapest about 2 years ago when AMD was winding down production and Zen 4 had been launched.