Hey Hun, nice to 'see' you on here again but sorry things are still rough in the sleep department.
I do think independent sleep is probably the way to change things. Routine to me looks fine (well not the WU time! But nap time and length and bedtime is I think ok for this age, though it's a long day with that early start).
I imagine there is a degree of chronic OT here which is not helping from constant broken sleep. But the main issue with independent sleep is that by the time LO wakes at 5.15 after 10 hours sleep the drive to go back isn't so strong, and with him needing you to settle I just think at this age having your presence at that time will be a drive to stay awake.
If it were me, now would be the time I'd be gritting my teeth and getting on with getting him to sleep alone. Probably using gradual withdrawal and reinforcing night time using a gro clock or similar. Is it something you are ready for? Happy to help with a plan if so x