Long documents slow Chrome/Chromium to a halt

While longer markdown documents are not super fast in any browser, there seems to be an overlap of performance-eating bugs or circumstances when opening long (>1000 lines) markdown files.

To Reproduce
Steps to reproduce the behavior:

1. Create a files with a variety of headlines, plain-text, and lists with sub-lists that is at least 10000 lines long. It doesn't have to be particular complicated, but long.
2. Open it in Chromium.
3. Wait a long time for it to render at all.
4. Wait a few seconds every time you try to scroll or edit the document.

Expected behavior
A maybe slow, but not unusable document.

Server details:

• Nextcloud version: 29.0.0.19 and 29.0.1 RC1
• PHP Version: 8.2
• Database: PostgreSQL 15.6
• Text app version: 3.10.0

Client details:

• OS: various Linuxes (Ubuntu, Arch, Debian)
• Browser: Chromium
• Browser version: 125, 126, and others
• Device: various laptops

Start by reproducing the issue with a 10,000-line Markdown document containing headings, text, and nested lists in Chromium, then inspect the browser Performance tab. The issue names no source file or test; done means the document opens, scrolls, and remains editable without becoming unusably slow.