Mouse selection jumps, disappears, moves things

[adjectiveNoun]

Hello. I am a new user of LM Cinnamon 20. So far the performance is great, but the various selection "features" make it impossible to work with written text.

Examples include: (^ denoting the cursor)

Assuming the selection starts as marked by ^:
Lorem Ipsum is simply dummy text of the printing^ and typesetting industry.

After moving the cursor left, the desired selection outcome is:
Lorem Ipsum is ^simply dummy text of the printing and typesetting industry.

Most of the time the outcome is:
Lorem Ipsum is ^simply dummy text of the printing and typesetting industry.

It seems that the slightest upward or downward motion resets the selection caret.

In some instances the selection decides to move some part of the text instead, resulting in mangled text:
Lorem Ipsum is ^xt of the printinsimply dummy teg and typesetting industry.

If the cursor remains motionless mid-press in whitespace for a second or so, the whole selection may deselect randomly.

Those behaviors make it impossible to work with any text or code. Editing this post itself was a PITA. Please point me to places where I can disable those things. The only thing I want the selection to do, is to select text between where it began and wherever the cursor is.

The actual mouse device is not the issue. I'm booting two systems, the other one being Windows 10 where the issue doesn't occur.

[SMG]

Welcome to the forum, adjectiveNoun.

Are you using Fractional Scaling for your screen/monitor?

Please give us information about your install by entering this command in a terminal: inxi -Fxxxrz
Click </> from the mini toolbar above the textbox where you type your reply and then place your cursor between the code markers and paste the results of the command between the code markers [code]Results[/code]. This will let us know how Mint sees your hardware.