This study presents a comprehensive analysis of 341 high-redshift galaxies (5 < z < 14) observed in nine JWST extragalactic fields, covering a total effective area of ~358 arcmin². Using conservative photometric selection (8σ), the team identified 341 galaxies, with 109 having spectroscopic redshifts. The rest-frame UV size–stellar mass relation is found to follow R_eff ∝ M*^0.19±0.03, similar to star-forming galaxies at z ~ 3 but scaled down by ~0.7 dex. The average size evolution over the redshift range is found to be slower than previously reported, with R_eff ∝ (1+z)^-0.4±0.2. A fraction (~13%) of the sample galaxies are marginally resolved in NIRCam imaging, located below the derived size–mass slope. These compact sources exhibit high star formation surface densities (Σ_SFR > 10 M☉ yr⁻¹ kpc⁻²), a range where only <0.01% of local star-forming galaxies are found. No evidence of ongoing supermassive black hole accretion is observed in galaxies with available NIRSpec data. A potential explanation for the observed high [O III]-to-Hβ ratios is high shock velocities, likely originating in intense star-forming regions. The rest-frame UV and optical sizes of the sample are comparable, suggesting that these early galaxies are building up their structures inside out and have not yet exhibited the strong color gradients seen at lower redshifts. The study provides the first large-scale systematic study of the galaxy size–mass relation at z > 5, revealing a consistent slope across the redshift range, with no significant evolution in the slope. The results are consistent with the idea that some massive galaxies in the sample may already possess a moderate amount of dust in their cores.This study presents a comprehensive analysis of 341 high-redshift galaxies (5 < z < 14) observed in nine JWST extragalactic fields, covering a total effective area of ~358 arcmin². Using conservative photometric selection (8σ), the team identified 341 galaxies, with 109 having spectroscopic redshifts. The rest-frame UV size–stellar mass relation is found to follow R_eff ∝ M*^0.19±0.03, similar to star-forming galaxies at z ~ 3 but scaled down by ~0.7 dex. The average size evolution over the redshift range is found to be slower than previously reported, with R_eff ∝ (1+z)^-0.4±0.2. A fraction (~13%) of the sample galaxies are marginally resolved in NIRCam imaging, located below the derived size–mass slope. These compact sources exhibit high star formation surface densities (Σ_SFR > 10 M☉ yr⁻¹ kpc⁻²), a range where only <0.01% of local star-forming galaxies are found. No evidence of ongoing supermassive black hole accretion is observed in galaxies with available NIRSpec data. A potential explanation for the observed high [O III]-to-Hβ ratios is high shock velocities, likely originating in intense star-forming regions. The rest-frame UV and optical sizes of the sample are comparable, suggesting that these early galaxies are building up their structures inside out and have not yet exhibited the strong color gradients seen at lower redshifts. The study provides the first large-scale systematic study of the galaxy size–mass relation at z > 5, revealing a consistent slope across the redshift range, with no significant evolution in the slope. The results are consistent with the idea that some massive galaxies in the sample may already possess a moderate amount of dust in their cores.