It is most likely infertile, but you should still might want to remove it? Idk if cross breeding is possible between budgies and lovebirds, and if it is possible it's certainly not likely, but maybe you want to avoid the eggs spoiling in the cage? Here's a listing for fake eggs that should be the right size:
https://www.amazon.com/FOIBURELY-Hatching-Lovebird-Lineoleated-Eggs(22mm18mm)/dp/B08NJT15XZ
When a bird is laying in my home, this is my process.
1) Calcium supplements. The easiest calcium supplement, if your bird will use it, is cuttlebone. My most prolific layers are doves, so they get calcium grit. But they do have powder calcium supplements you can sprinkle on food. Feeding egg or eggshells to your birds (scrambled eggs with the shells mixed in, no salt/pepper) is a good option for calcium as well.
2) Replace the eggs. While the bird is eating or playing, the moment she leaves her nest, quietly swap out the eggs. My doves are capable of fertilized eggs, so that's why I do this, but you may not need to. Some birds are too clever and reject fake eggs... you can try to fool them by microwaving the eggs for a few seconds so that they're warm.
* Do NOT just take eggs away without giving her eggs to sit on! She will just keep laying more to replace what you've taken away. If she rejects fake eggs, you might as well just let her sit on the real ones until she gets bored. If you're worried about the slimmest possibility that you might have unlikely crossbreed fertilized eggs you can candle them real quick.
3) Don't take it personal, but she's not going to want you anywhere near her cage right now. Laying female hens, or hens that are "incubating," can be mean as all get out. They hiss and throw a fit if you approach. Just let her get it out of her system. Don't try to touch or handle the eggs while she's sitting on them, if you need to for any reason wait until she leaves.
You do want to prevent laying whenever possible, so if you notice that she's particularly "fond" of any toys (masturbating on them)... remove those toys. If you notice she's shredding paper and starting a nest in a basket or something, take the basket away.