I would appreciate clarification on whether it is technically feasible within the forum’s current structure, or whether any workarounds are available.
Technically it's possible.
But don't you see the danger in that?
If the list were the same for everyone, it would be influencing each person's personal opinion, determining who finds it relevant and who doesn't.
A very valid point you made. if such a list were global, i agree it could unintentionally influence perception and elevate certain voices in a way that affects independent judgment

If it's an individual list, you run the risk of leaving behind users who make good contributions (in your opinion), but who for some reason are not yet on your list.
Furthermore, it could be missing the context of the ongoing debate, as well as the contributions of other users that may be relevant to the discussion.
Each debate is different from the other. A user might say relevant things in one debate, and less relevant things in another.
Even on an individual level, i agree there is a real risk of narrowing one’s exposure. Good contributions can come from unexpected users, no doubt and moreso, debates are usually context based . Someone highly relevant in one thread may be less in another.
There's already an "ignore" option that some users like to use (I don't), which ends up creating a filter to avoid reading someone's post that they don't want to see.
I also do not like the "ignore" option. However, your concern about context preservation can be treated by highlighting posts as suggested by @d5000 above, rather than reordering or filtering them out.