APK instalation (Android 11++) best practice

[alfware17]

Hello - I made some (for me) bad experiences with new mobiles (Xiaomi Note 11, A2 and Blackview A95) which I wanted to install some apps (Threema, Telegram, some own written). Ok I known from former Android versions: download and store the APK, install and if Android and/or Google ask if my sources are trustable - say yes. I dont do this every year so I was astonished, now Total Commander is not allowed any more to install - yes I read the story and I found the "uncensored version" and tried. What my question only is: how to install the Total Commander itself from APK if this is now allowed on the new mobile?! Well I did now by another manager (ES) one time and have uncensored Total Commander and can delete the ES. But on next mobile or other persons? How to first initiate the allow to install APK if the Total Commander isnt present at the first time.
Next qustion: is the restricton also for own written Apps/APK. Is there say no legal and easy way to spread and install by other people anymore? I wrote my apps in Java/Android Studio and do not upgrade them only update with some new data or fix bugs. But generally they are unchanged since Android 4.41 and the had installed and run where ever I can remember. Now not anymore? To speak truth, I am not really involved in that stuff. I wrote the apps in 2014-2017 and I do now only care having a runnable version of Android studio (3.2.1 is fine for me in Linux Mint and Windows 7-11) but didnt awaited troubles with I never could install them on the target mobiles...
And last question: dual apps... I found to be valuable to have more than one Threema/Whatsapp/Telegram in one mobile - well I have a lot mobiles and even more accounts, I am kinda messie that way. I learned, Xiaomi forbid/deactivated the builtin dual apps since Android update 11->12. So I now used App Cloner, which in general works fine BUT: says it is older itself and may work not the next 20 years and then again the install trouble and paranoia when installing from APK.
Anybody here who can tell me good practice for handling such - I would guess we can sum up under: dual apps and install own APK?
Sorry for my English - I live in Germany

[ghisler(Author)]

How to first initiate the allow to install APK if the Total Commander isnt present at the first time.

Just use a Web browser to download the apk, they still support APK installation. Or use adb install from a PC or Mac.

is the restriction also for own written Apps/APK.

The restriction is "an app installed from the Play Store may not update itself from outside the Play Store". Unfortunately Google's AI app checker is very dumb - although I blocked the installation of the Total Commander APK from Total Commander to implement this restriction, the AI still claimed that Total Commander could update itself. Therefore I had to remove the install function completely to not be banned from the store.

[alfware17]

Ok thank you for quick replay. I successful did my experiment: deinstall TC/mobile and apk installer, then open Brave browser and. looking for your uncensored apk which was already downloaded in a folder. Then Brave declared this file as "downloaded" and could execute/install.

Then I could also install my own apk and all runs fine so far.

But just for my interest: I "forgot" to care for the plugins the one and only main important on this mobile the wlan plugin. Ok TC recognized and made a new connection seems. But I'm not sure, the plugin comes from the play store, it doesn't matter? Or is the plugin needed to come from TC website too?

[ghisler(Author)]

No, the plugin may also come from the Play Store, the download versions and Play Store versions are identical.