I personally believe removing Tera Blast from the metagame is the cleanest choice and a very precise option that tackles the main problem I personally have with Tera. It is not the most effective, nor is it going to substantially change how Terastal is used in the SV OU metagame, but I believe Tera Blast is the catalyst behind a lot of what makes sudden matchup shifting so egregious. Compared to launch, there are legitimately a ton of viable ways in which Pokemon can use Tera Blast that aren't all that niche or fringe. From the S, A, and B ranks all of Kingambit, Dragapult, Dragonite, Heatran, Walking Wake, Basculegion, Iron Moth, Moltres-Galar, Sandy Shocks, Lilligant-Hisui, and Tornadus-T (with many more potential options) are capable of cleaving past standard checks of their choice with a perfect coverage or all-encompassing option. Of Pokemon that have been banned, Espathra, Volcarona, and Regieleki are broken with Tera Blast. Volcarona particularly is a rather unfortunate casualty as without Tera Blast it has a much healthier dynamic on the metagame, providing the tier with an extra option into Iron Valiant and Enamorus.
When a Pokemon is limited to its core movepool, matchup shifting only really takes it as far as its movepool enables it to. Kingambit doesn't necessarily need Tera Blast because Steel and Dark-type STABs are very self-sufficient, for example, but without Tera Blast, Volcarona and Espathra's checks become far more consistent, and they can only really delay the inevitable of losing the 1v1 with some extra HP/PP taken away since they don't have the option to, as easily, overwhelm them with pocket coverage. This is particularly important because it means that, regardless of a Pokemon's Tera, you know what the Pokemon is capable of beating by merit of its natural kit, and it's far more clear-cut to respond to certain Pokemon that can potentially spiral out of control with Tera Blast to round off their coverage.
Yes, Tera Blast does not exactly solve the key problem of Tera, but to me that's not really the point of removing Tera Blast. Instead, I believe that this restriction is more of a compromise of sorts that focuses on allowing Tera to cleanly remain in the tier and allows players to focus more on predicting and playing around Tera opportunities instead of being randomly sniped out of the blue or allowing Pokemon to beat Pokemon they shouldn't be able to.