Can you tell how good a GPU is just from its name?

The name gives you a rough starting point. Within a generation and brand, the first part generally identifies the generation and the later digits indicate the position in the lineup. For example, an AMD 9070 is a higher tier than a 9060. Nvidia models ending in 50 or 60 tend to sit lower in the range than 70, 80 or 90 models.

Suffixes matter too. Ti or Super on Nvidia cards and XT or XTX on AMD cards usually distinguish higher performing variants. Check the exact model though, because a newer generation doesn't automatically beat every card from an older one.

Use the name to make a shortlist, then check a GPU benchmark hierarchy or individual reviews. Look for results at the resolution you plan to use and in games you actually care about. A higher tier card can be faster without necessarily being worth its extra cost.

Start with your budget rather than trying to memorize the whole lineup. Compare the benchmark results and current prices of a few cards in that range. That also works for used cards, where the price can change the value calculation quite a bit.

Performance isn't the only thing to check before ordering. Look at the card's physical dimensions, power requirements and connectors too. A card can be a good deal and still not fit your case or work with your power supply.

Spec sheets can help with those checks, but I wouldn't rank different GPUs by boost clock alone. Use actual benchmarks for the performance comparison.