Waking at night. Help me figure out my 17 month olds sleep schedule

My son just turned 17 months and we have hit a rut with his sleep. He was sleeping fine a month ago before we traveled out of state and it was rough when we came home. Before we traveled his schedule was 3.75/3.75/3.75-4.

While we were traveling I had to rock my toddler to sleep and then transfer him or he would scream cry and would wake in the middle of the night. When we returned home we had the same issues of him not allowing me to leave the room and it took about two weeks before he was ok falling asleep independently.

I’ve been doing 3.5 cat nap/3/5-5.5 and he’s waking once in the middle of the night. Recently he’s only taking a 45 minute nap for the second nap and after we wakes up crying he’s falling back asleep in my arms. I’ve tried different variations of wake windows with some days we have success with sleeping through the night but I can do the same exact schedule the next day and he wakes up. I’m also trying for one nap with a 5/5-5.5 schedule but he is so exhausted by 4-5 hours that I’m thinking he’s over tired and so far has only been sleeping 1.5 hours for that one nap.

He has been my most challenging sleeper of my 3 children and now I’m looking toward you all to see what you advise.

TIA