Yes, Discord has some limits for Freemium users.
If this annoys you, you have to pay. There is currently no alternative method. With Nitro, Discord's premium service, you can increase your sending limit by up to 50MB.
The file limit is not the only restriction that Discord applies. Discord Avatar Size has also been subject to certain restrictions.
The current discord avatar size limit is 8 MB.
If you don't want to pay Nitro, you can upload the file somewhere and share the link on Discord. It's not so easy but not so hard as well.
If you know the way to bypass limit without pay and inside of discord, please share it with me. Have a beautiful day.