As an avid DIY-er, and competent (jointly with my wife) at designing bathrooms (and kitchens) - more imaginatively than seems common, and at very considerably lower cost, that is what I do and would recommend, even if you feel you need to leave plumbing to plumbers. Regarding plumbing, if I do myself I know there are no botches or corners cut, while I ensure future access to anything that may deteriorate (like shower controller) for future maintenance purposes
In my most recent bathroom I used panels for the shower. These were from the Allure range from Performpanel. The panel pattern I used had a choice of core material, moisture resistant MDF, Exterior grade MDF and Marine ply. I chose marine ply on the basis of being the most resistant in the (highly unlikely) event of any joints eventually leaking.
Panels are so quick and easy to fix compared to tiles, don’t suffer from discolouring grout, and have fewer joints to potentially deteriorate, and indeed with the nature of the joints, at least using the corner and shower train trims that I used, deterioration is less likely than tiles unless the tiles are on a very solid surface.
I used Performpanel’s coulour anodised aluminium internal corners, and their ‘panseal sealing strip’ at the bottom. The panels overlap the lip of the shower tray, and were stuck to the wall with Stixall, and using silicone sealant, well bedded in to prevent any possibility of leaks. The bottom seals were fitted as recommended by the manufacturer. For some joints where the silicone would be visible I used a coloured silicone (green to match the panels)
It was easy to fit and still looks brand new after 8 years of daily use.
(I used offcuts from the shower panels as bath splashbacks, trimmed with the manufacturer’s quadrant trims, and the same vertical internal corners as in the shower, both saving money creating a co-ordinated effect.)
I would have no hesitation in using such panels in my next bathroom project, however I would also consider terrazzo sheets.
Incidentally, a tip for the shower: a pressure equaliser before a mixer valve can help performance and longevity of a thermostatic valve, which I have found very effective in conjunction with acombi boiler system.
I’m away from home for a few days, otherwise I’d post a photo.