Hi,
I did a clean install of V7.5, as i was trying to sort out a banking app for another user on XDA, i installed magisk as normal with no issues, i have never had boot loop issue before but i have had a re-boot into recovery because i forgot to format data

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prior to the clean install, i dirty flashed from V7.4 to V7.5 with out any issues, no issues with magisk or anything,
once i finished installing Evo-x i always "Flash Current OrangeFox", reboot the rom and delete Magisk app,
reboot back into Recovery, install Magisk V25.2, reboot the rom re-install Magisk v25.2.apk.
Like you, this is the method i have always used with out any issues,
Have to tried to change slots after installing Magisk

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Thinking back i am sure that Aggelos advised a "format Data" when upgrading from a previous version of Evo-X

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Also for me if things start to get a bit weird, starting from a almost STOCK rom normally fixes things,
i then use MIGRATE-GPE to backup my apps and data for safe keeping.