Window frame gap fillers

[Turnyourtvoff]

We’ve been painting the walls around our windows and to do so we have removed the sealant - the idea was to paint and use a mould resistant sealant (we’ve had condensation and water build up issues before) however the gap is very large. Does anyone have any suggestions on what I should use in/down the gap before finishing with sealant? Insulation? I think it had some decorators caulk but the gap expanded since the work was done and under the seal and I removed was some hard and brittle white material.
Thank you

 

[foxhole]

Maybe white trim .