In my case, if I say that, I use two wallets. In one, I keep my Bitcoin holdings that I plan to hold for the long term and I keep them in a separate wallet when I need Bitcoin to meet some needs in my daily life. I use my emergency wallet from which I directly trade on the central exchange. That's all, but I never install my holdings on my mobile or any device, rather I write the seed phase on paper and store it in a very safe place.
Your practical story sounds like you have two wallets: one is non custodial, second is custodial (exchange account). In generally, your practice is good, and I agree with you but if possible, I think you will need to have another wallet, a third one, that is a hot wallet that is used for payments. The third (hot) wallet will be small one, with your small fund, for regular payments.
In addition, your first wallet (non custodial) that is used for storing your main (big) fund, needs to be stored on a different device than a second, and third wallets. This separating storage is helpful to prevent complete loss of all your fund that can come if you store all funds in only one device.
