Please help me improve my 10.5 month old's sleep

[Mahonia]

DD is 10.5 months old. Never been a good sleeper. I'm sure she's not sleeping enough but I just can't get her to sleep any more than she is.

She has been feeding to sleep but I'm working on this and making good progress at bedtime - she usually self settles after a bottom pat and a song to calm her down. This can take up to 30 minutes. For naps she has a feed, gets snoozy and I put her down awake albeit very drowsy and she rolls over and goes to sleep. But she only ever naps for 30 mins. Very, very occasionally she's managed an hour or more, but this is really rare. She does a 30 min morning nap, then does 30 mins at lunch. When she wakes at lunch I feed or cuddle her back to sleep to ensure she gets another 30 mins. So nap total each day is around 90 mins. She's tired when she wakes up from her morning nap but I can't get her back to sleep.

She usually wakes twice overnight. When I first tried to get her to self settle at bedtime she slept for around 9 hours straight for the first three nights, then went back to waking twice a night. Often she's awake for an hour for one of the wake ups. She wakes for the day any time between 06:15 and 06:45.

An average day looks something like this:

Wake 06:45 (usually been awake in the night for anything up to 1hr 15 mins, so total sleep after midnight is often only around 5-6 hours before wake up).
Milk feed dependent on if she had some in the night and at what time.
Breakfast 07:30 - 08:30
Morning nap - 30 mins around 3 hours after waking up although often she poos just as she's getting sleepy which sets us back at least 30 mins.
Lunch 11:30 - 12:30 ish
Lunch nap - 30 mins around 3.5 hours after wake up from morning nap. Fed or cuddled back to sleep for another 30 mins.
Dinner 17:00 - 18:00
Bedtime around 4 - 4.5 hours after waking from lunch nap.

What can I do to improve her sleep?? How can I encourage longer day naps? She can link sleep cycles as she has done it occasionally, she just doesn't seem to want to do it regularly.

Any advice would be really appreciated.

Thank you.