Which is better for heavy multitasking?

The HP Envy 17. Its 12-core i7-1260P and 64GB of RAM run far more apps and browser tabs at once than the 10-core i7-1355U and 16GB in the HP 17.3". The HP 17.3" is fine for everyday work.

Which screen is sharper?

The Envy 17. Its 1920x1080 IPS panel shows noticeably more detail than the 1600x900 panel on the HP 17.3", and IPS gives better viewing angles. At 17.3 inches the difference is easy to see in text and photos.

Neither maker publishes a battery figure for these configurations, so judge by the chip. The U-series i7-1355U in the HP 17.3" draws less power than the P-series i7-1260P in the Envy 17, so it should run longer per charge.

Is the Envy 17 worth stepping up to?

Yes if you keep large files or run many programs at once. You get four times the RAM, double the storage, a sharper screen and Windows 11 Pro. If you mainly browse and write documents, the HP 17.3" covers it.

Do both have a backlit keyboard?

Yes. The HP 17.3" adds a full-size numpad. Both are 17.3-inch laptops, so expect a similar footprint and weight.

Can either play games?

Only lightly. Both use Intel Iris Xe integrated graphics, so they handle casual and older titles but not demanding games at high settings. The Envy 17's extra RAM helps more with apps than with frame rates.

HP 17.3" Touchscreen Laptop vs HP Envy 17 17.3" Touch Laptop

The Envy 17 is the stronger machine: a 1080p IPS touchscreen, a 12-core i7-1260P, 64GB of RAM, a 2TB SSD and Windows 11 Pro. The HP 17.3" is the lighter, simpler pick with a newer 13th Gen i7-1355U, a backlit keyboard with numpad and Wi-Fi 6, but its 1600x900 panel is soft for a 17-inch screen. Buy the Envy 17 for heavy multitasking, large files and business software; buy the HP 17.3" for everyday browsing, documents and media on a big touchscreen.

Choose the HP 17.3" if you want a current 13th Gen i7, a backlit keyboard with a numpad and Wi-Fi 6 for everyday work and streaming.
Choose the HP Envy 17 if you run many apps at once, keep large files locally and want a sharp 1080p IPS touchscreen with Windows 11 Pro.

Prices

HP 17.3" Touchscreen Laptop: $989.10 at Amazon (checked today)