City in Peninsular Malaysia to immerse in Malay language?

I like to self-study the local language in the places I travel to. I don't do courses or attend classes.

I just arrived in Kuala Lumpur, Malaysia. It's a very multicultural city and though most signs are in Malay most of the spoken language I hear around me is English, Chinese, or one or another Indian language.

Other than going to Indonesia where a different variety of essentially the same language is much more universal, which city here in Malaysia would be the "most Malay" linguistically?

I'm aware that across Malaysia there are a good few other languages and dialects related to Standard Malay to various degrees, and I expect there will be lots of ethnic Chinese and Indian Malaysians everywhere, but I wonder if somewhere else (Johor Bahru? Penang?) might be more immersive if I want to hear and practice Malay with the most people every day in shops and restaurants, etc?

(I'm focusing on cities just because I find them easier to "live in" for longer periods than smaller towns or villages. I'm focussing on the peninsula because I intend to travel overland from here.)