LTE is configured as an Ethernet interface on MikroTik. The speed limit is configured in queues. Before this, you need to mark up traffic to the prerouting (connections) and postrouting (packets) IP/Firewall/Mangle. Dependence of speed limits on the time of day and days of the week can be done in two ways. Firstly, you can make several queues and switch them on a schedule. Or, you can make one universal queue with multiple branches and set the marking of packets in the mangle depending on the time. Limit on traffic volume can be done in IP/Firewall/Filters. But everything becomes more complicated if you need to make a limit per user. It is necessary to discuss everything before starting work. By time and money, I wrote two days in each of which for 4 hours. But if it turns out that you need to do everything easier than I think, then one day and 2-4 hours will suffice.