I'd say it depends on how much you DCA? I mean it might break the pattern but really, investing idk $40-$50 per week with $10 fees does not seem worth it since that's 1/4 of your total investment already. Maybe set a maximum in terms of fees so that you can guarantee it, and if it goes past that, just hold the money or something temporarily. If you can't hold it then actively look out for hours where the Mempool isn't as congested to get cheaper fees.
LN sounds good if you want to though. There are a lot of guides out there and there are also ones in the forum made by others as well. If you really don't want to break the pattern then I'd suggest go for that, but if you can handle breaking the pattern then it's up to your preference by then.
I would say when we are talking about putting in fiat, that doesn't really include that much money to do. I mean from my bank to bank account of binance to put up money, that is nothing, it's free and I do not spend any money at all. That means I have money at binance for free, now that I do that, I turn that fiat into bitcoin, and that only costs the trading fee as well.
This means, I can do DCA with absolutely no fee at all, just a small trading fee, which is less than a dollar. So, I can put up 50 bucks a week and that would be fine. I would still say go for it if you want to, sure transactions cost a lot but in this situation you are not having any crypto transaction. If you do have to, then suddenly that becomes a trouble and you would be right, you shouldn't have crypto transactions at that level per week, it would hurt your finances, but if you do what I said then you do not pay anything and you can do that. I know, because I have done that for years.