IgluCruise is a specialist travel agency, that gets good reviews on TrustPilot:
https://uk.trustpilot.com/review/www.iglucruise.com
I suggest using their website as a starting point when seeking a suitable cruise for your needs, simply because you'll find cruises from lots of different companies listed there:
https://www.iglucruise.com/cruise/fjords-and-norway/any/any/any/any/any/any/any/any/any/no-fly-cruise
(Use the filters, on the left, to help you find exactly what you want).
You can then choose whether to book through IgluCruise or to look for your chosen cruise on the website of the relevant cruise company.
Cruising doesn't appeal to me (or to my bank balance!) but, if it did, I wouldn't even consider booking any cruise without checking out the reviews on CruiseCritic first:
https://www.cruisecritic.co.uk/
(Start typing the name of a ship into the search field and then click on the relevant result. Read through the general information first and then click on the 'Reviews' tab, at the top of the page).
YouTube is also a good source of cruise reviews.