What’s a good size for “Cache data size” on shared hosting

We have a slow shared hosting. Installing this has helped a lot with the Admin area speedup. (Website was already helped by WP Rocket, a caching plugin that’s much better at multilingual websites than others.)

Now, sometimes when logging into Admin area after a day or two, the first time load is VERY slow. Like 10-15 seconds. Only change we’ve made is installed this plugin.

I wonder if the Object Cache is somehow causing this delay? What should the “cache size” in settings be? I’ve kept it at 35MB right now.

Below are our cache performance numbers:

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And here are our settings for now: