I’m sorry you’ve had to come and join us on the bad ship MS, but welcome anyway.
Have a look at https://www.mstrust.org.uk/about-ms/ms-treatments/ms-decisions-aid
All the disease modifying drugs (DMDs) are detailed. Your neurologist was right that Copaxone, while it’s easy to take/inject, and has few side effects, probably wasn’t strong enough. And now that there are so many better drugs available, it makes sense to take something with a bit more welly.
You need to weigh up the effectiveness of the specific drugs together with how well taking them will fit into your life and their potential side effects.
Generally, the more effective, the more possible side effects. But, and it’s a big BUT, taking as good a DMD as you can is likely to pay dividends for your future. Avoiding potentially disabling relapses is the aim of the game when you are newly diagnosed.
For people like me, having had RR/SPMS for more than 20 years, initially even the less effective drugs weren’t available, and subsequently I’ve had side effects from 3 different DMDs that’s meant I couldn’t take any at all for most of the time. I’m now quite badly disabled.
Take your neurologist and your MS nurses experience and opinions on board, but make sure you are happy with the drug you end up taking. After all, it’s your body and your future. You need to be certain you are taking the right medication for you. With most of the DMDs, if you don’t get on with them, it’s easy to swap. With a drug like Mavenclad, it’s action is longer lasting, so it’s not so easy to swap over (doses are taken in months one and two, then twelve months later). But I’m sure that your blood tests would show up any untoward effects after month one so it’s not as risky as it sounds.
Good luck with your drug choice. Feel free to come on here and ask as many questions as you need to. Since Cladribine/Mavenclad is a fairly new drug, we generally have less experience with it, but there will always be someone who can advise. Try posting on the Everyday Living board for personal experiences of the drug. That might help.