Can I get a tourist visa after visiting Cambodia if I'm in Thailand on a 45-day exemption?

In long term it's better if you got the visa that you could stay here with no issue, definitely better than hopping in and out of the country, depends how long you would like to stay here tho 😊

Do you want a tourist visa or are you happy with a visa exempt entry? Currently visa exempt drops back to 30 days at the end of march. When the time comes speak to a border run company, they won't take you if they think you will have a problem re-entering. If you want a tourist visa you have to go to an embassy wherever rather than just to a border, but your Covid stamps might be an issue. If you plan on staying here you'd be better getting a long term visa

You can do a land border-hop after your extension, and then extension again after that. Cost about 3500baht

Did you have a return or onward flight booked when you entered ?

What is your visa / covid extension history?