Problems with Batflat 1.3.6 on localhost and on commercial server

[radik10]

1/ on localhost, on xampp-windows-x64-7.4.29-1-VC15 is working amin panel (backend), but frontend shows template with error 404. Page is loaded and is not possible to navigate to other pages

2/ on live server (apache, php 7.4) is possible to add name and password on login page, but after this there is “Internal Server Error“ (white screen with black text). In log file is: “core:error AH00124: Request exceeded the limit of 10 internal redirects due to probable configuration error. Use 'LimitInternalRecursion' to increase the limit if necessary. Use 'LogLevel debug' to get a backtrace.” On this server is no problem run other CMS like Joomla or WordPress.
Why so small CMS (Batflat) has to be so demanding on requests?

3/ on localhost, with developer mode on, there is error in top of admin panel “Deprecated: The behavior of unparenthesized expressions containing both '.' and '+'/'-' will change in PHP 8: '+'/'-' will take a higher precedence in C:\xampp\htdocs\lc.batflat\inc\modules\statistics\src\Chart.php on line 11”

Thank you