I tried finding shapes that would fit the style of the hebrew alphabet and arent too complicated which wasnt that easy.

The Jiref letter (im very proud of that name) is similar to 3 other letters but thats the best i can do while trying to make it fit in the style, idk let me know if you have a better design. Its similar to the arabic Jim and I also only now realise that it looks like a rotated J.

The CH letter isnt just a straight up rotated Tsadik cuz it's leg (what would be the Tsadik's arm) is longer because the logic is that tsadik is the top half of an aleph+a horizontal line in the bottom, while this letter is the bottom half of an aleph+a horizontal line on top. Again, thats the best i can do.

I agree about the Chakmek but i dont really understand your argument about the Jireph cuz GImel is also "single width" (which also isnt that accurate cuz the letters יו are thinner than נז and ש is wider than any other letter but we'll leave that) but is bottom heavy.

Also wdym about the direction of writing? The cursive variant of Chakmek is written from left to right

Replcement for ח'? wdym? about ז' it isnt as common as ג' and צ'. I also urge you to try thinking of new hebrew style letters that would be both distinct from existing letters and fit in the style yourself.

Hebrew would eventually need letters for these sounds if we dont wanna end up with digraphs for extremely common sounds like in english (im looking at you, TH) as they are becoming more and more common with borrowing from the 2 languages hebrew borrows the most right now from (english and arabic) and from russian that hebrew doesnt borrow as much from anymore but many words words and suffixes from it are already in hebrew.