SignTools VS SignTools-Builder

check this out https://github.com/SignTools/SignTools (personally haven't tried it)

There are two components to self-hosting SignTools, the web frontend, and the actual signing server, the latter of which must be run on macOS. Fortunately there's a guide to set it up so that you use GitHub Actions as the signing server, which gives you a certain amount of free minutes per month. I've never gotten close to the limit, even when I'm signing a few dozen apps. The guide also shows you how to set up the web frontend on Railway, which also offers free monthly credits, so you can actually self-host both components for free: https://github.com/SignTools/SignTools/blob/master/INSTALL-SIMPLE.md

SignTools (it's nice for developers with Apple Developer Accounts), for regular users it's kind of a hustle

The SignTools developer (tool that I used to sign other apps with working push notifications) said this about the document posted above:

im new to this i used to use appdb but i kept getting revoked so now i got a dev account for me to make apps and also use it to sideload idk what app to use , i saw some people talk about SignTools to get notification is there any other way to get notification other than that app? i only use it for cercube and rocket insta so please help

Keeping the original bundle ID is required, but not enough for PN working. You have to use a distribution certificate & an explicit profile with the correct PN entitlement. AltStore/Sideloadly cannot do it so you have to do it manually. I recommend you take a look at SignTools if you need working PN: https://github.com/SignTools/SignTools

This is quite easy to do if you are using SignTools. When signing an app, make sure to select Use custom when choosing bundle identifier options and specify it in the aforementioned format. When it's signed, your sign in should work.

I think what you're trying to do is use your own M1 Mac as a builder/signer, right? You can do this using https://github.com/SignTools/SignTools-Builder. That way, the entire signing process stays completely within your own devices.