Thankfully I have been managed to move past the bug that I came across.
At the dialog screen when talking with Sigurd next to the dead body of brother Paul, choose to blame Basim. The other two options resulted in the game glitching out again.
After a long black loading screen the cut scene managed to play and I was able to carry on with the quest and progress further in the game.

Downloaded the latest patch v1.0.4 and STILL the glitch remains on PC for the 'Blood from a stone' quest when a cut scene should play right after speaking with Sigurd about the stone being taken and standing next to the dead body.

I had the exact same issue.
After browsing the forums and I came across a 3rd party tool. Use Google to find 'Flings trainer' for Assassin's creed: Valhalla.
Load the game up in window mode first then run the trainer app.
Load up your last saved game and after the dialog option to speak with the people, on the trainer app adjust game speed to 10.0x.
You'll have to wait 5 to 10 minutes but you should be able to start the next mission in the Viking long boat.

Same issue for me playing on PC. First was 'blood from the stone' mission, now this. After googling and going through forum posts Came across some helpful advice. Use google to find 'Fling's Trainer for AC Valhalla'.

Run the game then the trainer, play the game and when you get to the final cut scene to give a speech to the people, select your desired choice and activate the trainer to speed up the game to 10.0x.
Wait about 5-10 minutes and that should get you to the open sea and the start of the next mission.

Thankfully I have been managed to move past the bug that I came across.
At the dialog screen when talking with Sigurd next to the dead body of brother Paul, choose to blame Basim. The other two options resulted in the game glitching out again.
After a long black loading screen the cut scene managed to play and I was able to carry on with the quest and progress further in the game.

Downloaded the latest patch v1.0.4 and STILL the glitch remains on PC for the 'Blood from a stone' quest when a cut scene should play right after speaking with Sigurd about the stone being taken and standing next to the dead body.

I am playing the game on PC. I managed to get through the door though the moveable item was floating above a crate that can be destroyed.
Was able to see the body of brother Paul and interact with the dialog. After the cut scene where Basim says " Soliders, Edwyne's here" the screen fades to black, saving icon appears for 3 minutes then the character appears at the bottom of some steps where I am unable to move the player but can pan the camera around the character. I can press 'ESC' to quit the game or access the options screen but all other keys are disabled.

I've lowered the graphics settings down to the lowest possible setting and restarted the game in hope to get it working and even gone back to a previous save and had no luck.
See image below where the game has crashed.