I personally use L-usdt to selfcustody usdt because of low transaction cost, privacy, security.

But if you aim to reach more mainstream, you should go for eth and trx. Txn fee on trx is rising while erc20 token are becoming less costly to send on eth chain

But I think these 3 chain would still be intact as long as tether stays in the game. Sometimes terrible idea could live for decades (for example, climate change).