Well i think 70c is a bit high for the bed for PLA. I like 50 or 60 with the glass. But that is not your problem. The cheap azz extruder in your ender3 uses a ptfe liner that is sadly sensitive to higher temps and can be deformed and cause these problems. If it were me, I might be trying to entertain some kind of all metal hotend conversion. Maybe something genuinely from E3D. Just so you know you don't have to worry past the installation.