Where to start for a new family bathroom June 2022

goldfinches

I suggest you have a think about your bugbears with your existing suite and room and when you go to the showroom or fiddle around with an online planner you use that list to help you decide which items you're going to buy. You could change the lighting, have a different mirror or make the room easier to clean and so on all of which would make your lives pleasanter in future. 
There's loads of articles here Bathroom ideas, designs, trends and pictures | Ideal Home plus an online planner among lots more advice here Bathroom - Find Bathroom Furniture Inspiration - IKEA.

Ant555

We refurbished our only bathroom at the end of last year. Its a tiny room and our only loo so we needed to get it right and plan.

We did the visits round the showrooms but also invited a 'mobility' bathroom installer to quote as they also do standard domestic installs .  As they said to me, they often fit wet rooms or install for people with reduced mobility that can splash a lot of water so they are very used to making things water tight.
Im happy to recommend by direct message to you if you are Manchester, South Manchester, Cheshire area.

As Goldfinches points out - lighting can make a massive difference - we got LED downlighters fitted and its miles better than before.
We replaced a bath with a walk in shower (we never used the bath)  but I guess with little ones, you might not want to do that
We took everything off the floor so its easier to keep clean and also makes it appear like a larger space - Tall boy cupboard on the wall and wall mounted sink unit.

We had a working loo every evening - were without it for about one working day during the day.
Be prepared for the job to take 7-10 working days - ours took 9 but that included me changing my mind over something plus a day where they had to redo the ceiling due to a manufacturing fault with the materials.
Do ask them what they are going to do with your floor - if its an upstairs room then I guess you will currently have floorboards or chipboard with something on top - will they fit it out with plywood before installing whatever flooring you select perhaps? - Will you go for Tiles (can be cold), LVT (warmer) or other vinyl options perhaps.  We went for LVT and although I cant vouch for the longevity as its onlly 8 months old, I am mighty impressed  and it feels really warm underfoot.
Ceiling - will it need skimming or will you consider upvc ceiling panels.
If you are after design features then does the layout lend itself to a 'feature wall' with complimentary tiles - we did this along with the main/long side of the shower and are very pleased with the result.
Do you currently have an extractor fan - if no then ask them to put one in, if yes then is it modern? as replacing it with an inline decent air flow one will add minimal cost to an existing install.
Do you need a shaver/elec toothbrush charging point in a wall cupboard - or even a fancy mirror with a built in light.

I hope at least some of the above assist you in your quest.