Try adjusting the volume mode by turning leveling on, if that feature is available on your device.
How to use volume modes on your Roku streaming device | Official Roku Support
You said you "pay for channels through Roku" and are seeing ads. You might prefer to pay for some channels that are available ad-free. Some examples are: Max, Paramount+, Prime Video, Netflix, Disney+, and Apple TV+. I haven't watched a channel with ads on Roku since 2016, so it can be done.
The ad-free based over how much money you can provide! If someone is on a fixed income this can be extremely difficult if you want to watch different channels! I have no issue with the ads itself. But its the volume of the ads that's the issue!