"Replace Photoshop" is too abstract question. Photoshop is an app that have huge amount of totally different tools, so what exact tools do you need to replace? Each generation of Photoshop have some new useful and useless options, so what exact Photoshop version do you need to replace? Photoshop is not ideal or perfect tool. Same as other apps it have pros and cons. Other apps may have unique tools that outperforms Photoshop, as well as limitations that makes them worse than Photoshop in some areas.
Cool thing about PhotoLine is that developers listen to users and quickly add missing options if possible, For example you can check thread "List of important things available in Ps but not available in PhotoLine" here
https://www.pl32.com/forum3/viewtopic.php?t=6952
Some PhotoLine cons:
PhotoLine UI panels and sliders have no global pretty skin. (UI concept looks similar to Photoshop CS versions in 2005-2010
https://www.versionmuseum.com/history-of/adobe-photoshop) UI looks different in macOS and Windows. But due same reason UI feels very fast. You also need to install custom Icons and Shortcuts set for UI because original icons are very bad and original shortcuts not too logical.
PhotoLine Brush soft edges are 8-bit only, so you can't paint in Linear gamma. Photoshop brushes are better, but not perfect as well. They use 10 or 11 bit, and they also can't paint smoothly in Linear gamma. Affinity brushes use true 16-bit.
PhotoLine "Remove Brush" is OK, but not so "smart" as "Content-Aware Spot Healing" brush in Photoshop. It works very well for single spots, but can't detect correctly long scratches on grainy uneven surface. Actually i tested similar scratches in many other apps and they all behave worse than Photoshop CC 2018.
Layer Styles not ready yet for serious design work yet. They are not so advanced as in Photoshop and too limited in size. Some of them are still 8-bit only. Layer Styles engine in PhotoLine still under development and should be improved soon or late. Also there is no quick and easy "Fill" slider near "Opacity" slider.
PhotoLine don't have yet Mean, Median and other image stacking modes. So no Temporal noise reduction.
HDR Merge in PhotoLine can merge only 2 or 3 frames and exposure steps between frames should be the same (for example -1, 0, +1).
Panorama stitcher is fully automatic. It don't have any option to select spherical or flat/planar projection.
Text can't snap or align using true edges of the letters. For some reason it use fixed boxes around letters and align only to those boxes.
PhotoLine don't have "Puppet Warp" tool.
Crop Tool have no "Centered" toggle.