I start transitioning my Reception class in the summer, likewise the Year 2s are gradually transitioned into the ways of the Junior part of the school. I wait till after Easter though for most of it!
I do encourage independence though (and offer no choice to the bulk) in terms of their belongings and changing. From Day 1 they unpack their bag and pack it again in the evening. Of course I verbally say “has everyone got their water bottle? Their lunch box? Go and get anything left in the cloakroom”. Plus putting their books and drawings in their tray, work in my box etc. I push for personal habits such as doing their own shoes and changing for PE from the beginning and work hard on this with them.
But the vast bulk of their work is done in small groups in EY whilst the rest choose in free play. So in the summer, I do start to do lessons, starting just once a week, where, after the input, they all sit at a table from the start and begin their task together with me and the TA working round. It takes time for them to learn that a staff member can’t always be right there with them and to think about solving their own problems (for example fetching themselves a number line or a word card). It’s tricky because they are little (some won’t be 5 until the very end of summer) and the learning style should be play based, but I do think it’s cruel on the children and the new teachers to not even start to introduce more independent and formal learning.
As summer goes on, I also start to stretch them that little bit more by keeping the work going - so they can’t just do their sentences with the high frequency words in and wander off, they do that bit more, because in Year 1 they can’t just go and play once they’ve done the main objective.
Its a hard one OP, but if there’s one thing I’ve learnt at my school is a teacher who is fully set in their ways will likely not change for anyone so it may be you that needs to make some adaptions to ease them in, however unfair that is.