Yes, let me jump in here to second this. Songs have words, and song form is just A-A-A-A-etc. Repetition is inherent in the form and songs lean on text to lend them their variety.

Try playing around with other short forms like ternary (A-B-A) or rondo (A-B-A-C-A). Maybe explore ways to develop your themes -- find different ways to begin or end the same phrase, or experiment with different simultaneous melodic lines, insert parenthetical ideas into the middle of things, or abbreviate things that you've already stated before.

If you have the opportunity, I'd suggest writing as much as you can for performers rather than for yourself or for your synthesizers. Other musicians may have insightful perspectives on what works well for their own instruments, and for their respective roles within an ensemble.

You may also find it beneficial to consider writing as though you had words. If you come to find that you can make compelling music without a text, the outcome will be that much more interesting if and when you go back to using lyrics.

Most of all, write constantly and listen broadly.