Don't feel like a failure, it's a shock to the system after nearly two years of easy bedtimes with DS who had a nice little bedtime routine and went quietly off to sleep.
Once your boy can climb out of the cot, I agree you don't have much choice but to move him into a bed and toddler-proof his bedroom.
If you’re worried about your boy wandering about at night, fit a stair gate across his bedroom door or across the top of the staircase to make sure that he’s safe.
Toddlers test our limits but learn through repetition ie making a fuss and raising noisy objections doesn’t alter parental set boundaries. Stay consistent.
Quite often they sense being rushed so dig their heels in even more. Allow an hour to get him to bed. Avoid any TV or tickles and rough stuff so he's not over stimulated.
Stick to the same routine.
Eg Bath or flannel wash, nappy change and pyjamas or whatever he wears this time of year, clean teeth and into bed.
Then gentle chat, story or 3, maybe a lullaby? Cuddles and time for bed.
Just wondering, do you find he is more clingy by day than previously?
(Btw if your neighbours do ever comment just say he is going through a phase so sorry for any extra noise early evening but you're working on it).