11 month old - does this sound like under or overtiredness?

[TurtleMum]

My 11mo can self settle and used to go down easily at bedtime most of the time. All of a sudden, he’s really struggling at bedtime. During the bedtime routine, he seems tired - looking drowsy during feed, yawns, face rubs, cuddles in when I sing him a song etc. I then put him in his cot awake and he lies there shuffling for 5-10 mins and then starts to sit up and crawl around his cot, stands up etc but lies down inbetween and rubs his face on the mattress like he’s trying to go to sleep. He then sits up and repeats the process. It looks like he’s trying to sleep but struggling. No tears at all. He’s completely silent. I’ve never seen him struggle like this and I don’t know what’s wrong? Does this sound like under or overtired? His wake windows are 3/3.5/4. Or could it be regression?

Thanks

If he's not crying then probably nothing is wrong. He's just taking a little longer to self-settle.

What's the end result? He goes to sleep by himself, but it just takes longer?

@NuffSaidSam The best outcome recently is that he falls asleep by himself in 20 minutes but on the worst day, he quietly did his up and down routine for half an hour and then started crying and was really difficult to soothe and I ended up breastfeeding him to sleep - it took over an hour in total that day. Until a week ago, he used to fall asleep really within 5 mins or so.

Anyone else?

My LO stopped being able to settle himself to sleep at about 14 months. He went from being able to settle off to sleep by himself in his cot in ten or 20 mins, to howling when I lay him down and taking a long while to resettle in my arms.
I started down a strict(ish) path of sleep training, letting him wail and sob, but it was too awful. In the end I let him go back to napping on me like a newborn, falling asleep in my arms at night if he needs it.
I don't know what brought about the change. Maybe brain growth and increased awareness actually made him more fearful of being apart from me?