Keeping betting money in its own account

A separate account makes the balance a fact rather than a feeling, and makes the amount lost or won visible without any calculation.

Money mixed with rent is money whose loss carries a second consequence, and that consequence changes every decision made with it. A stake that might affect something else is not a stake being sized on its merits.

It also protects the rest of your finances from a bad run mechanically rather than by willpower, which is the only protection that works on a bad night.

What follows from that is less comfortable. It is the cheapest control available and the one most often skipped, because setting it up takes an afternoon and the benefit only appears later.

What to do with it. Open a separate account, fund it once, and treat topping it up as a decision rather than a reflex.