Having slept on this: I think you should (through your fiancée) talk to your in laws about expectations
In the UK, families tend to do many of the smaller events at home and then hire a hall for 1 day, or at most the sangeet then the wedding and reception
You could hire an Airbnb for the home ceremonies (which are not parties) for the close family of 18 only
Its more expensive to have a wedding in the UK than in India so Asian weddings are scaled back vs here
If the family want to pay for accommodation and flights for a large number of guests, then you both going to India might just be better: if the grooms parents are paying then they can arrange and pay and you just turn up
Otherwise have a scaled back Asian wedding, 110 guests , 1 day of ceremony & reception, but understand what budget you have for that minus flights & accommodation
Get the guest list together
Look now for a venue, and local airbnbs for hosting guests to understand what the costs would be (including flight costs). If a flight is eg £400 for multiple guests your budget won’t go far
Btw: I have always paid my own flights to India /elsewhere for family weddings (same when family come to ours) and usually stay in family’s home with them (or other relatives). So push back on flights coming out of your budget /let the family take what they need for flights out
You CAN have a nice Asian wedding with events etc for 110 on much less than 100k, start mapping it out and then decide