Jep, like many here indeed confirmed and mentioned, no UE5 for HLL. There are no benefits there, it would lower the performance for many, plus not all players are at highest NVMe speeds to support texture and geometry streaming.
Plus PhysX is gone in UE5, meaning most of the game needs to be remade, that would be near impossible and not beneficial to anyone.
Destruction would also take a huge part to performance, but mainly to available/required bandwidth. There is none for many players, they are at the max atm. So destruction would then need to cut into playercounts, which is not happening.
So, there are no benefits of improvements to make on those fronts. 4.27 has lots of cool additions, so fingers crossed that upgrade will be smooth if or when it happens.