My recommendation would be Libre 2 with the OOP2 app as a bridge and no need for additional hardware.
I used that approach for a couple of years and only changed when I had the option to have a CGM connected to my pump.
Lol, mine was cheap too.. The market is flooded with decent used high end devices that cost nearly 1k on release then traded in favour of the latest.. (mine was.) Reconned to a decent standard & sold for a song..
“virtue signalling” is not my style. But I do like bang for buck…
I recommend the xDrip facebook group.
It is administer by developers of xDrip who are incredibly helpful when things don't go to plan and contains links to software and documentation under the Files tab.
I know some people are reluctant to use Facebook. If that is the case then sign up with an email you use for the sole purpose of Facebook and only subscribe to that group. You get a lot more help from the dedicated team than from a group of random people with diabetes of which many manage their condition purely by diet.