installation fails before last step

[ngrmm]

I exported a profile and wanted to install it on another webspace. I've done this hundred times and it works always.

But this time the install-process fails before the last step. The screen where you can enter admin name and password does not appear. The browser gives me an 200 Error for install.php

I can not login into the backend (no user account set yet).
At the frontend I get different errors. Looks like any functions linke css() (ProCache) and render() (Formbuilder) causes errors.

The server is running php 7.4 and mysql 5.7
PW is the latest masterversion

the install.sql in my exported has a 16.4mb filesize
the phoinfo() says 120 max time for php executions. Could this be the problem?

the first frontend errorlogs after installation fails:

2021-12-14 15:06:19	?	?	You must assign a template to the page before setting custom field values (name1062) [pageClass=ProcessWire\Page, template=]
2021-12-14 15:06:19	guest	https://xxxxxxxxxx.com/_new2/	You must assign a template to the page before setting custom field values (name1062) [pageClass=ProcessWire\Page, template=]

one after some refreshes in the browser

2021-12-14 15:21:50	guest	https://xxxxxxx.com/_new2/	Fatal Error:  Uncaught Error: Call to a member function css() on null in /homepages/21/d521107727/htdocs/xxxxxxx/_new2/site/templates/_inc/header.php:50 Stack trace: #0 /homepages/21/d521107727/htdocs/xxxxxxx/_new2/site/assets/cache/FileCompiler/site/templates/home.php(4): include() #1 /homepages/21/d521107727/htdocs/xxxxxxx/_new2/wire/core/TemplateFile.php(327): require('/homepages/21/d...') #2 /homepages/21/d521107727/htdocs/xxxxxxx/_new2/wire/core/Wire.php(414): ProcessWire\TemplateFile->___render() #3 /homepages/21/d521107727/htdocs/xxxxxxx/_new2/wire/core/WireHooks.php(951): ProcessWire\Wire->_callMethod('___render', Array) #4 /homepages/21/d521107727/htdocs/xxxxxxx/_new2/wire/core/Wire.php(485): ProcessWire\WireHooks->runHooks(Object(ProcessWire\TemplateFile), 'render', Array) #5 /homepages/21/d521107727/htdocs/xxxxxxx/_new2/wire/modules/PageRender.module(554): ProcessWire\Wire->__call('render', Array) #6 /homepages/21/d521107727/htdocs/xxxxxxx/_new2/wire/core/Wire.php(417): ProcessWire\PageRender->___renderPage(Object(Proce (line 50 of /homepages/21/d521107727/htdocs/xxxxxxx/_new2/site/templates/_inc/header.php)