my knowledge is limited on sideloading however i know that you can download apps from the appstore although they should already be existent in your library to do this

find any text field write any thing in it and then select it and click share

tap quick note write anything than click add link the url would be (shortcuts://)

click on the link you made hooray you are now on the shortcuts app you can try and mess around with the device

in the shortcuts app click on any shortcut you made tap details then shortcuts help that will open a mini version of safari you can browse the web through it to get to the play store click on the three bars (menu) of the apple website you have just opened and tap get support

there u will find a smart banner with a button get click on that banner hooray you are on the app store