How to automatically change dot to comma in google docs?

Question

Google Sheets

did not find in tags google tables.
When entering numbers into the table, if they are separated by a dot, then the formulas perceive them as text, not a number.
100.21 is the number and everything is buzzing.
100.21 - text and formulas break.
How to solve the problem? The table can be filled not only by me, but the result of the calculation is visible only to me. Constantly use search and replace completely crap, you need to somehow automate, thanks for the answers!

Answer 1

I recommend using the regular expression
=REGEXREPLACE(A2; "[.]"; ",")

Answer 2

Try to press in the document:
File / Table settings / Regional settings / Russia or USA / Save settings
Meaning "change" different countries in the document settings. It says that this affects data formatting, this is because the decimal separator is written differently in different countries

Answer 3

Data format settings.
There is also a cool function:
CTRL+F, "More Options", "Find and Replace"