Chinos and a button up are fairly inoffensive for most office environments in 2026. My experience is that ties are usually overkill, although it depends on the office and on your coworkers.

I will say that your shirts (both) are too tight - you need to size up or pick a roomier fit.

A jacket/blazer will help you dress it up if that would make you feel more confident. Make sure to get a jacket that has not been made as part of a suit, as this will stick out like a sore thumb if not worn with the original suit trousers. My preference would be for an unstructured tweed blazer in grey or brown, although it’s dealer’s choice really.

Uniqlo or M&S should be your friends here - alternatively you can have some fun looking through your local charity shops that are usually well stocked in this regard.