The fitting in your link is made from Polypropylene, that type of plastic will not solvent weld. Fit it into the top end of the waste valve if that's you preferred choice, otherwise I'd fit a standpipe and hook the drain hose into that. https://www.screwfix.com/p/floplast-washing-machine-trap-white-40mm/18640
Any pipework under the floor I would solvent weld, it's fit and forget, and no danger of a joint coming apart and/or leaking at a later date.
Any pipework under the floor I would solvent weld, it's fit and forget, and no danger of a joint coming apart and/or leaking at a later date.