To get a severance you require a long period of bad performance to get a severance. If you wanted to find an employer to wait a couple of years sure, but you won’t be let go that quickly and if you did you’d likely have violated a policy that would null your severance.
I’m fine if you just want to work your given work hours (37.5) and not go the extra mile or work yourself senselessly and in most cases people should refrain from that unless trying to shoot up hierarchy. But just purposely underperforming and not giving at least your base work effort a go just amounts to impacting your team members. You may think your sticking it to the big guy but your just a number on a human resource spreadsheet your actual impact is to your colleagues filling in the gaps for you.