My employer went the MDM way, works really well. But updating charts or performance databases still need to be done by the crew in the app itself, basically part of preflight preparation. As mentioned, the iPads are still not quite as optimized for multitasking and most apps need to remain open to update their content. Our charts app is the worst offender, having to rebuild its document index every time, which can take up to a few minutes.
I do find that if your iPad is not the latest and greatest, it can sometimes struggle to keep multiple apps alive in memory without reloading them when you switch to them. Our iPads are 6th Gen mostly, and we generally need a charts app, performance app, and journey log/navlog app open at the same time. Some days it works fine, some days it will need to reload the apps every single time you switch between them.