@Maker_of_Things I had a quick look and cannot find an A13 compatible build for your phone on Lineage (nearest is A21s), Jolla Sailfish, Graphene, Postmarket or e (nearest is A21s). There are other OS available that I haven't checked. Nor do I know whether you can unlock your bootloader to actually flash a new OS. Anyway, before all that I suspect that the profi's would ask 'what is your threat model and 'what are you aiming for'. Since if you want 'security' and 'banking apps' the answer that comes up a lot is Graphene which permits a 'sandboxed' google play store - but only runs on a Pixel afaik. I have converted both a Pixel (to Graphene) and a Motorola (to Lineage) both via ADB command line, It was nerve wracking but successful and I am only a trainee nerd. If you can read German check out Kuketz and his blog for de googling phones. Gd luck!
