My husband had an ASCT after revlomid induction for three months, for IGG Lambda myeloma. He had about 7 super hard days and a few months of recovery. Eleven months later he had his second both at Mayo Rochester. Again he had some pretty hard days, but they passed. This time he got a complete response. He went on low dose revlomid as a maintenance for two years and did not relapse for 6 years. Then a year of treatments gave him a few more years treatment free. Now he is 13 years out, 8 months into treatments again, and his numbers have been zero for 3 of those months.
He did collect enough cells for a third transplant but he is too senior to want to do that now.
It sounds like you have had 6 cycles of treatments, and weighing your next move. ASCT are definitely short duration aggressive treatment in hopes of long term gain. Have you been evaluated at a large cancer center or university that does transplants?