Hello great modmaker! Thank you for resurrecting this cool mod and of course for that you're implement that awesome so-long-wanted performance optimizations here!
So I want to insert my coin too and have done this pack of updated (new HR tech images) and highly-optimized (all files are less than 1MB now) GFX! Hope you like it and use it in your fork! Thank you for your hard work and hope you'll do more performance boost-ups in updates!

https://drive.google.com/file/d/1oNsMTB8nIJjeZMzsOZ7V59PADm0fPkuu/view?usp=sharing

Best regards!

Nice!
I'll add these files in 1.1.11
I really like the new heat/fluid techs, and the lighter item icons look great aswell

A few notes:
The external overlay technology doesn't look right https://i.imgur.com/GFgemGA.png
I'm keeping the old version for now

Would you mind making a hr version of the factory-circuit-connector? It's the only low res texture left in the mod

Oh, sorry, I see... I redone this icon so I think it will looks better now. Also I provide you some different samples of circuit-connectors in 64x and 128x (and tech images with the same connector's gfx) so you decide what samples you'll use in mod.
https://drive.google.com/file/d/1V0uS_P_hcGijbexQKom1YCu8bEZbmk09/view?usp=sharing

p.s. well then... I remember one thing... So about 5 years ago there was another interesting "written from scratch" clone of factorissimo1 for Factorio 0.14 that was coded especially to have maximum possible performance (because factorissimo1 has huge performance problems that time ago). I bet that mod may content some unique code decisions that can be useful or implemented in our case to provide yet some more better performance. If you are good in LUA, please inspect and do some analysis of https://mods.factorio.com/mod/Free_Real_Estate - so maybe you can find some really useful code stuff.

Am I must redone this another way? Or this is ok?

These new graphics are good. I'll add them in a future update. Been a bit busy this week.

Added!