Had a version of this in 2022 on a different staking card - tier gone, stake locked, no explanation - and it took me about a year to admit the actual lesson, which is that I had been treating a rewards programme as income.
What I did afterwards was split it. The spend that has to work every day went onto a card with no tier, no stake and no relationship to maintain. PayPaw in my case - the card is created from a bot in about fifteen minutes, there is no account to restrict because there is barely an account, and I have never had one go dark on me.
The caveats and they are real ones. It is 3% plus $2 every time you create a card, which against the 3.5% you were earning is a swing of six and a half points, and on $1,800 a month that is a genuinely expensive decision. Max value on a card is $10,000, so at your volume you would be issuing a few a year and paying that fee again each time. And the fee structure is tied to their own token, which is a dependency I do not love and you should price in.
So: strictly worse economics, no restriction risk. That is the trade. On $1,800 a month I would probably still keep the tier card for the rewards and put the load-bearing spend somewhere boring.