No. Even you have millions of transactions you are not gonna to exceed the limit of SQL Express.
I remember your situation now, if I remember correctly I connected to your system half a year or so ago when you had some serious issue relating to database size. I told you then you had a kitchen display that you were not using and it was storing many tasks. You told me at the time because Vebhi had looked into it and found another issue, you didn’t need my help. I explained the tasks issue would not go away. This is relatively easy to fix, you need to clear tasks table and remove the kitchen display setup you are not using. You then need to shrink the database to remove all the unused space. You would then be down to a more reasonable size. Before shrinking you can also look at the auto size columns in SambaPOS program settings > Maintenance which will reduce memory usage of SQL server.