Prevent phone auto-connect to a specific wifi connection, without forgetting that connection The feature I am looking for exist on MIUI rom and samsung roms:



Similar question were asked before: 
This from 2015 has an answer about Samsung and MIUI roms only.

Answers to this and this question  (both from 2013) offer workarounds. 

An answer to this question suggested to use Wi-fi Ruller which unfortunately is not supported anymore. 

It looks like the questions are rather old, and a simple, straight forward direct solution is yet to be found.
From what I can see, there really is no way to do it directly

There are root workaround but nothing that only allows manual connection (excluding Samsung or MIUI stuff); it must be OEM implemented. I can't find any way to do it in standard AOSP or lineage OS

You could always try something like Tasker and have it shut off WiFi when your in range of a network you don't want to automatically connect to