MacArthur bi-passed as many Japanese positions as he could manage and it saved many American lives. Thousands of Japanese corpses were found on some islands after the war. They had starved to death.
Yes, WW II was horrendous. Churchill and many of the British High Command were initially against what was to be the Normandy invasion because they were sure that trench warfare would be repeated.
I did an essay about D-Day and the passage below is part of the bibliography.
The Battle of Messines, 1917
https://www.firstworldwar.com/battles/messines.htm
The Battle of Messiness helps one appreciate the anxieties aroused from memories of Gallipoli, the Somme and Passchendaele, where the British suffered catastrophic losses for gains of only yards. By some historian assessments, the most successful attack by British forces in WW I was the Battle of Messines in 1917. The battle lasted June 1-12, and involved 216,000 men of whom 24,562 became casualties. They attacked on a five-mile front and penetrated 10 miles.
Taking this battle as a starting point, the Normandy invasion from five beachheads established a lodgment about 10 miles deep on a 40 miles front. The effort required 50 days. Therefore, a WW I veteran could make an optimistic estimate of about 400,000 casualties, given he completely disregarded the fact that the D-Day landings were significantly more hazardous than any offensive attempted on the Western Front. In fact, by July 24 there were 120,000 casualties.