the power grid is severely broken, the electric heater is difficult to use, the batteries do not work as before, they are reluctant to fill up even when there is plenty of energy

Batteries have a transfer limit, by chaining up a ton of them all in buffer mode they end up using all their transfer capacity just by flinging power left and right. Either invest in better batteries, use capacitors or use diodes to prevent the batteries wasting their transfer capacity doing nothing.

I tried to use diodes to differentiate the network, but before the 4935-4936 update everything was very good and these minor energy losses could be considered as inductive heating. at this moment, the power grid is in an unplayable state, I think it's worth rolling back the changes to update 4921

This is the result of player error and not actually an issue with the new update. There's no universe where the old energy system is reintroduced due to its horrible performance compared to the new energy system, and your issues with oscillation can be easily solved by adding diodes (you're supposed to separate your input from your output on batteries).

I mean there are some things I could do but every minor change has the very real possibility of breaking things that are more important. I can run some tests, sure, but I can't promise that there will be a fix for that.

I literally spent 2 hours trying to store energy in different ways. In the end, I just removed all the energy storage and just laid the wires, but the energy network works when you rearrange the blocks of wires, as if the network does not work after some time.

Most likely fixed with the most recent version, large clusters of batteries should no longer waste transfer capacity just ping-ponging energy around while not doing anything useful, which is most likely the phenomenon we've seen here.

Energy got rewritten again in X4942 and should work pretty much exactly as it did before the new system, if possible please test your setup in the new version.