It is really up to how you want your plant to look. Personally, I prefer 1 stem/trunk. Others like multiple. I would also shorten up all those more lanky looking branches on top. I do not think plant would look so good with thick top branches and not so thick lower parts, but that is JMO. Having main trunk thick/fat at the bottom and sort of tapering toward top would be my preference. All those lowest branches are quite etiolated - I have similar problem growing under lights during winter. I would cut them off or shorten them all considerably - leaving them on for another season or few helps to 'feed' main trunk and thicken it. Pruning etiolated branches definitely helps to thicken them up IMO - skinny, long branches with widely spaced leaves vs short and full.

BUT really, lots depends on what you want. If you want tall plant with bushy look (many stems) it would be different than keeping plant on shorter side, solitary, with thick trunk. Pruning any etiolated branches would help in either case - plant would look better if short or tall, multiple trunks or solitary. It is definitely good time to prune.

Thank you for the comments and suggestions! Just realized I only included one plant and not the other, which I've now attached below in case anyone has any additional recommendations