Are DT Swiss wheels bigger than other makes?!?

Recently acquired a pair of 2nd hand DT Swiss X1800 and am finding it difficult to fit tyres on them as too tight. Have tried a Maxxis Beaver & and Swalbe Nobby Nic, both have gone on eventually after a big loss of blood, sweat & tears but I would not fancy fixing a flat in them when out riding. Never had problems fitting a tyre over he last 30 years.

Have tried various methods – washing up liquid, levers, ensuring bead seated properly and other various methods on youtube.

Not tubeless and don’t want to go down that route on these wheels although big fan of no tubes.

Any recommendations on easy fit tyres on DT Swiss X1800 wheels appreciated, I don’t think my thumbs can take it much longer!