Yes, I also went with the S10+ 1Tb storage and 12Gb of ram and ceramic black like you. I no longer worry about space for apps, music, video, pictures etc and I've noticed no lag at all period.
My work phone is a Note9 and it's a great phone also. I do use the Spen on the Note to capture customers signatures and that's probably the only time I ever use it. I'm sure there are others that use it constantly and it is nice that you can use it to snap pictures and such.
Yes, the SD card. That was also a must for me, even with my 1Tb of storage. Just pulled it out of my old phone, popped it in and all my saved documents, pics, music were right back on my S10+. I also wanted the headphone jack. I have a really nice pair of over the ears headphones that sound amazing! But they're 1/4" so I have to use an adapter to go into the headphone jack. I haven't found a pair of Bluetooth buds that can even come close to the sounds I get from those headphones. So, if you really want and need the Spen, get the Note10. If you want crazy storage, ram, SD card slot and headphone jack, go for the S10+ ceramic edition. It really depends on what you "need" with the phone. Hope this helps you a bit! I'd say you really can't go wrong with either models.