How old is the battery?
What type? Wet cell, gel, sealed?

Modern batteries are generally good but yours might be a rogue poor one or simply reaching it’s natural demise.
It might be worth getting yours tested as a first step plus alternator and possible unwanted current draw from wiring or component problems. Can you try another battery in the car to see if that does the same? Make sure your earth connections are clean and good, especially battery to starter. That can either be direct or not depending on the layout. Morgans with batteries in the rear use the chassis as a connector so a couple of earth connections to go wrong.

My Mog has an Odyssey maintenance free battery. It was on the car when bought about 8 years ago so actual age unknown. 40k miles done but only 1300 in the last year (Due to lockdowns. It has only failed once when I had left the lights on and drained it ( 2 ?) years ago. Cteck brought it back ok. I leave the Cteck connected by direct battery connection using supplied connection cable. No starting problems.
I had a Focus for 10 years and the battery failed after 9 years. High mileage commuting so no low mileage issues.

Plus Four MY23 Furka Rouge