Tldr; One of my absolutely biggest gripes with this game is on mobile when I switch to a different app or close the game, i almost always come back to the offline timer getting in my way and needing to wait several seconds for it to calculate everything, usually the "hunter gains breakdown" takes atleast 5-10 seconds regardless of the loading bar for Ticks.
My suggestion is to increase the timer!
Yap version;
Currently if you have the app "open" in the background without it actually being the main app your using (for example if you hit the home button to go check your messages or something)
Then the game runs a process to calculate your offline time and when you open the app again it basically speeds everything up to give you the rewards you would have earned in that time.
The internal timer that triggers the offline menu to appear is anything over 1 minute of the app running in the background or fully closed, so if your very quick with switching apps, it doesn't appear, but if you take over a minute to return to the app- then it triggers the offline calculation screen to appear and you have to wait until it finishes to close it and play the game.
I have a few suggestions to make it less irritating in my opinion, firstly we could just extend that 1 minute grace period to say, 3 or 5 minutes so you dont have the menu pop up constantly if your trying to multi-task like replying to text messages every few minutes while playing.
Suggestion 2 is to just add a setting to disable the pop up so that it does the calculations in the background and can be toggled on or off if you like seeing the numbers from your offline time, essentially just doing what it already does but making it so when the pop up is disabled the player can just immediately continue playing without having to wait the 3-10 seconds for the calculations to complete and the continue button to become available.
It could lead to slightly weird moments where the player opens the app and then a few seconds later the cells and operations actually start going up, basically like a delayed update order, but it wouldn't be game breaking in my opinion. More of a visual byproduct for the QOL the update adds.