Water Pump Pulsing at Lower Water Flow

So just arrived in the north and it's great to be back in Thaland after too long away dealing with 'stuff' back home !

....and with the temperatures down in the morning = wanting less water flow on the shower to get more heat out the electric shower unit before 7am..when the water hits a lower flow point where it is hot...it pulses water (strong/down to almost nothing every few seconds) vs a consistent flow...like when you stand on a hose etc briefly.

Is there any way to dial the pump next to the water tank so the water is consistent and nice and hot ? 

I'm living in a friend's place and they are away just now and I'm trying to help out with issues in the place while here.....bit rough around the edges.

Have a handyman for all the rest of the stuff but he does not know about pumps/tanks/waterflow stuff.

Edit: Chatgpt says...

2. Shower or piping flow is too low to keep pump running

Many pumps need a minimum flow rate to stay activated.
Signs:

Spurt happens only at low flow.

If you open another tap slightly, the flow stabilizes.

But I wonder if there is some dial in tanks you can turn with a screwdriver for lower pressure constant output etc