You don't need to sign an LRSA to use the prefix; there are some legacy holdouts still using their original prefixes without any agreement or fees with ARIN. Signing an LRSA will give you access to ARIN IRR/RPKI/rDNS/etc services, which can be quite useful, though.
I'd recommend creating an IRR route object for your prefix and ASN on AltDB (or finding a sponsor to do so on your behalf). Once you have that in place, you should be able to announce it without issues, without any ARIN involvement. Growing adoption of RPKI filtering may make this increasingly difficult in the future, though.
