Any MVNO offering plans with multiple eSIMs?

I have been using IIJ's ファミリーシェアプラン for many years now: while it offers way more data than I need per month, it is the only plan I could find that allows getting multiple SIM cards and sharing the data allowance between them (I use it for two phones and a Surface).

With the new iPhones going eSIM only, I find myself wondering what I'm going to do going forward, since IIJ stopped offering the plan and the replacement is limited to a single SIM (also fuck paying 2,200 yen to change a physical SIM to an eSIM or 3,300 yen to sign up with them again).

I checked the usual suspects – Mineo and Line Mobile – but it seems no one does plans with data sharing across multiple SIMs. Am I missing something?