Just my opinion but I feel they should not build so many 054As. It's not really that survivable nowadays with only 24-32 mid range SAMs. If we treat it simply as an ASW platform as many here have said, it feels like more 056s would be more cost effective
In recent years Korea/Japan have really upped their game in terms of numbers/missiles/tech and even Taiwan is loading up Ta Chiang with ~20 missiles
It's no longer feasible to try to overcome Japan/Korea/Taiwan/US with numbers alone. I'm worried that China might be devoting too much manpower/money into a class that could possibly become sitting ducks
If they were building 20 054As without having built a large fleet of destroyers and without building more destroyers in the future and without building 054Bs in the future, then I would agree with you.
But let's not forget that 20 054As are being built in context of the overall expansion of the PLAN's size, with a significant number of world class destroyers already recently built (see the run of 055s and 052C/Ds so far) and with more to come this decade, and we know 054B is likely going to start kicking in as the last of these 20 054As enter service as well.
Going forwards into the medium term future, I expect PLAN's fleet of 054As will likely serve in a similar role to what their current 053H3s/two 054s serve, except significantly more capable for their respective era (especially in terms of ASW, and to an extent AAW) and more upgradeable.
I.e.: they will be multirole patrol frigates mostly relegated to green water duties (though able to operate in blue water if needed), mostly meant for low intensity opponents, but able to contribute as part of a high intensity conflict when operating alongside friendly air power and naval task groups.
They would certainly be vulnerable in a high intensity conflict if they had no friendly air power and more capable naval task groups to support them -- but frankly if that's what a conflict has come to then the PLA would have much larger issues at hand than the survivability of their 054As lol.