Tether announced they'd discontinue redemptions and freeze remaining tokens on Omni and a few other legacy chains, effective Sept 1, 2025.
If they can do this and get away with it, how are people still trusting Tether on other chains?
All stablecoins are tokens that can be frozen, minted, burned and upgraded by the issuer. There may be exceptions but that is not the norm. That is how things work, you are simply out of date. While it may not be considered normal or desirable, it is the standard and has been for a decade. How else would they be able to freeze any tokens that are suspected to be part of criminal activity, other than when they hit some platform? That's how compliance for these things works, and it is not going to change for the better.
Plenty of tokens used a transition method and they tend to similar cut off dates for claims, otherwise they would have to support everything indefinitely. They can never be certain if some balance is lost or whether someone is simply not responsive to the change. Often they do this when changing from a different layer of the same blockchain or when transitioning to another blockchain. That is why cutoff dates are given otherwise they would have to support even ghost chains forever, which from a business side of things makes no sense. You are responsible for your own money. Shitcoins are not a buy it and forget about it kind of adventure.
Also, hunting for a whale/recovery service in public is like putting a "please DM me scams" sign on your forehead.

That is a general problem that has no good solution. If someone is not connected or does not have contacts that are in similar position, how else do you find people? You can either announce publicly or approach privately. However, private DMs of this kind are even more scrutinized so eventually OP would just get his account blocked by Telegram, X or wherever else he would try that.