I'd not use the softcups. I was TTC after a MMC for 3 years. Because I was charting, I knew how often we had sex and when. The month I fell pregnant over 3 years ago, we had had sex for 5 days in a row over my fertile period. Well when I miscarried, we started trying again but not the same sex pattern so one month, decided we would try it and bam, got my BFP again but that turned out to be a chemical. Then 2 years passed with no BFP (don't know why we waited so long) and we tried that pattern again but I used the softcups but AF turned up. Also used pre-seed. The next month, tried the same pattern with pre-seed but without softcups and got my BFP.
Between me and my husband, we obviously aren't the most fertile of couples, but the month I used the softcups, I did wonder if it could potentially be hindering our chances because there's no way you can guarantee you are locking all the sperm up around your cervix. Some could be on the opposite side of the softcup and therefore not get to where it needs to go. Sperm swim upwards anyway so I would say avoid using them.
Good luck girls. Hope your BFPs are all just around the corner x