Solved syncs only extensions from the Chrome Store, but not manually installed

[ComputerJoe]

I had the Webstore and Crypto token disabled in Vivaldi -- Settings --- Privacy.
I installed the extensions manually in developer mode on my windows 10 computer.

Now I have started using a second computer, a Mac.

In the Win10 computer, I have 17 extensions (and sometimes up to 26) installed.
vivaldi://sync-internals showed 0 Extensions and 26 Extension Settings (see on the bottom)
Once I installed one with the Chrome Shop the number of extensions moved to 1. So only this single extension did the sync.

My expectation is that

• Extensions installed in developer shall also sync with Vivaldi sync.

• But currently only extensions installed via Chrome Store sync.

Can anybody explain why this behaviour?
Why all these privacy settings and the focus on Vivaldi privacy, when at the end we must stay with Google?

Vivaldi 5.1.2567.66 (Stable channel) (x86_64)
Appendix: sync internals
Bookmarks 1146 1146 Running
Preferences 106 106 Running
Passwords 1 1 Running
Autofill Profiles 0 0 Datatype preconditions not met. Not Running
Autofill 0 0 Running
Autofill Wallet 0 0 Running
Autofill Wallet Metadata 0 0 Running
Autofill Wallet Offer 0 0 Running
Themes 1 1 Running
Typed URLs 3 3 Running
Extensions 1 1 Running
Search Engines 6 6 Running
Sessions 24 24 Running
Apps 1 1 Running
App settings 0 0 Running
Extension settings 26 26 Running
History Delete Directives 0 0 Datatype preconditions not met. Not Running
Device Info 4 4 Running
Priority Preferences 2 2 Running
Reading List 0 0 Running
User Events 0 0 Datatype preconditions not met. Not Running
User Consents 0 0 Running
Send Tab To Self 0 0 Running
Security Events 0 0 Running
Web Apps 0 0 Running
Sharing Message 0 0 Running
Notes 10 10 Running
Tabs 0 0 Running

[Komposten]

My guess is that with extensions in the Web Store, all Vivaldi has to sync is the URLs to those extensions, and then the browser can install them by itself. If you install an extension manually from a file, Vivaldi would have to also sync that file to its servers in order to send it out to all your devices, and that can potentially use up a lot of storage space on the sync server (as well as extra bandwidth when syncing).