Due to the system architecture of iOS/iPadOS, unless jailbroken (don’t go there!), your iPad/iPhone is not susceptible to traditional malware infection per-se. However, as with all computer systems, there are still vulnerabilities and exploits to which you remain vulnerable.
While your iPad/iPhone are unlikely to be directly infected by malware, it is still possible to easily download or transfer an “infected” file to the device - which if transferred elsewhere still has the capacity to infect other computer systems with malware. If you are moving files between devices and other computers using USB storage, you should always be mindful of the potential risks in moving potentially infected files.
Should you wish to add a degree of useful protection to your iPad, whilst acknowledging that there are no bona-fide anti-virus products for iOS/iPadOS, there are a small number of Apps which do add useful defences. Browser and network-based attacks can largely be mitigated by installing a good, Content and Ad-blocking product. One of the very best and most respected within the Apple App Store - designed for iPad, iPhone and Mac - is 1Blocker for Safari.
https://apps.apple.com/gb/app/1blocker-for-safari/id1365531024
1Blocker is highly configurable - and crucially does not rely upon an external proxy-service of dubious provenance. All processing takes place on your device - and contrary to expectations, Safari will run faster and more efficiently.
1Blocker has also introduced its new “Firewall” functions - that are explicitly designed to block “trackers”. Being implemented at the network-layer, this additional protection works across all Apps.
As for your "occasional" volume button malfunction, perhaps you can provide more details of the symptoms and circumstances of the issue.
