If I request a new number for my landline, will the new number have scam calls attached to it from it's previous owner?
Changing your number won't stop the scam calls. At best it might give you some temporary respite from them. At worst you might be allocated a 'new' number which comes with its own unwelcome history attached to it.
You may have features on your existing phone which can be activated to reduce the calls (such as 'do not disturb' timing features, VIP ringtones for known callers in your address book, area code blocking or withheld number blocking). These can reduce the impact of the scam calls a bit.
Better to look at getting a call screening device, or a phone which does that. There have been numerous posts on the forums about how to reduce, or eliminate, the scam calls and also some recent feedback from customers who have had success with the call screening approach.