In short: no.
Bonding means two or more physical links are configured to form single logical link, but that has to be done on both ends. Usually ISPs don't offer bonding ... If using two physical links without possibility to configure them into bond it is possible to configure load sharing, but configuring it so that it works reliably is really not trivial.
It's number of LTE modems which defines number of physical links. SIM cards only offer means of authentication to modems and a modem can only use one at a time.