I would switch right now. Be mindful of what long-term commitments you are making when switching and try to avoid them if possible (eg: 24 months of bill credits for a trade-in.) Easy for me to say because I just buy my phones unlocked and can switch at any time, but I’m not getting any incentives.

I also do the dual-sim thing right now. Kind of a waste of money but it allows me to use another carrier as a backup or to just keep an eye on them to see when and where they are better. Verizon as my primary carrier, I have an eSIM on T-Mobile for $10/month 2GB data as a secondary. I also have Dent on another eSIM which uses AT&T. I don’t get raw AT&T speeds on dent but it’s a cheap efficient way to be able to use AT&T’s coverage if I ever need to (and I never do.)