Here's what your sump return needs. One of these,
https://picclick.co.uk/AN-6-AN6-JIC-Flare-MALE-FEMALE-SWIVEL-371566058971.html#&gid=1&pid=1
Plus an M16 to AN6 adaptor and a AN6 blanking plug. Of course you then need to make up a new drain hose with AN6 100 series hose 1 straight and 1 30deg AN6 fittings and a M16 banjo assembly. Making the hose is cheap and easy, probably around $100us and the sump fittings the same,easy to fit. You can then have easy oil drain via the blanking cap and nice looking blue and red anodised alloy AN fittings for everything.
Here's mine
The easiest way to achieve the "magnet" thing is to fit a Filtermag tn. to your now external filter. If you fit it at the 6 oclock position it also provides some rock protection to the filter from the front wheel. I have 2 of these fitted to the cars.
https://4wdindustries.com.au/products/filter-mag-reusable-magnetic-oil-filtration-filter-life-extender-ss375
Ciao