If you already have Collada files and they import ok, then you shouldn't need to remodel them.
Option 1 - Here is a recent ArcGIS blog post about locating Revit files (but should work for other files as well) using the georeferencing tools: https://www.esri.com/arcgis-blog/products/arcgis-pro/3d-gis/geolocating-revit-files-in-arcgis-pro/
Option 2 - Use the editing tools in Pro to manually move, rotate and scale the model into position.
Option 3 (My preferred method, much more accurate, really helps if you have a known from point in model coords and the corresponding to point in real world coords) -
Import your model into file gdb multipatch using the Import 3D Files tool. Check the extents of the multipatch in the Properties under Source->Extent. Most Collada files will be around 0,0,0. Your from points in the next step should be using coordinates around here.
Move the multipatch in x,y using the Transform Features tool. Needs a link feature class with from, to polylines. It doesn't matter if you don't have 3 from\to coord sets, just put some offsets in, for example: 0,0 to x,y; 10,0 to x+10,y; 0,10 to x,y+10. If you need to do any scaling (feet to metres etc.) you can do that here - just need to work out correct values to use.
Shift the model up or down in z using the Adjust 3D Z tool.
If required use Define Projection to set the appropriate coordinate system. I have found sometimes that the extents of the shifted model are not correct - you can use the Recalculate Feature Class Extent tool to fix this.